private void invoiceListToolStripMenuItem_Click(object sender, EventArgs e) { if (_instanceInvoiceMaster == null) { CloseAllForms(); _instanceInvoiceMaster = new Invoice.InvoiceMaster(); _instanceInvoiceMaster.MdiParent = this; _instanceInvoiceMaster.FormClosed += instanceInvoiceMasterHasBeenClosed; } else { ShowMessage(); } _instanceInvoiceMaster.Show(); }
private void instanceInvoiceMasterHasBeenClosed(object sender, FormClosedEventArgs e) { _instanceInvoiceMaster = null; }